Machine tool, control method, and control program

Abstract

This invention provides a technology for controlling the coolant temperature, taking into account the temperature rise caused by the heat generated by the pump. [Solution] A machine tool having a workpiece processing area comprises a first tank for storing coolant, a cooling device for cooling the coolant stored in the first tank or the coolant before it is sent to the first tank, a pump for drawing up the coolant stored in the first tank and sending the coolant to the processing area, a first temperature sensor for detecting the temperature of the components constituting the machine tool, a second temperature sensor provided in a flow path connecting the pump and the processing area for detecting the temperature of the coolant flowing through the flow path, and a control unit. The control unit controls the cooling device so that the temperature detected by the second temperature sensor approaches the temperature detected by the first temperature sensor.

Description

Technical Field

[0001] The present disclosure relates to a machine tool, a control method, and a control program.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2008-142801 (Patent Document 1) discloses a temperature control system aimed at controlling the temperature of a coolant circulating in a machine tool with high precision.

[0003] More specifically, the temperature control system controls the coolant to a target temperature in heating control. Before the heating control, the temperature control system cools the coolant to a temperature lower than the target temperature by a predetermined temperature. Thereby, the temperature control system widens the adjustable temperature range in subsequent heating control and more reliably matches the temperature of the coolant with the target temperature.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, when the coolant is pumped up by a pump, it is affected by the heat generation of the pump. Therefore, the temperature of the coolant rises when passing through the pump. Due to this, the temperature of the coolant discharged to the processing area may become higher than the target temperature. The above Patent Document 1 does not suggest anything regarding the rise in the temperature of the coolant due to the heat generation of the pump.

[0006] In view of the above points, a technique for controlling the temperature of the coolant in consideration of the rise in the temperature of the coolant due to the heat generation of the pump is desired.

Means for Solving the Problems

[0007] One example of the present disclosure provides a machine tool having a workpiece processing area. The machine tool includes a first tank for storing coolant, a cooling device for cooling the coolant stored in the first tank or the coolant before it is sent to the first tank, a pump for drawing up the coolant stored in the first tank and sending the coolant to the processing area, a first temperature sensor for detecting the temperature of the components constituting the machine tool, a second temperature sensor provided in a flow path connecting the pump and the processing area for detecting the temperature of the coolant flowing through the flow path, and a control unit. The control unit controls the cooling device so that the temperature detected by the second temperature sensor approaches the temperature detected by the first temperature sensor.

[0008] In one example of this disclosure, the second temperature sensor is provided in a flow path that supplies coolant affecting the temperature of the workpiece.

[0009] In one example of this disclosure, the machine tool further comprises a spindle configured to mount a tool. The second temperature sensor is provided in a flow path passing through the spindle, or in a flow path connected to said flow path.

[0010] In one example of this disclosure, the second temperature sensor is provided in a flow path for supplying spindle-through coolant or side-through coolant.

[0011] In one example of this disclosure, the machine tool further comprises a tool post configured to mount a tool. The second temperature sensor is located in a flow path connected to a discharge port for supplying coolant from the tool post to the workpiece.

[0012] In one example of this disclosure, the above-mentioned component is a bed.

[0013] In one example of the present disclosure, the machine tool further comprises a second tank for storing coolant. The coolant stored in the second tank is supplied to the first tank, and the cooling device is provided in the second tank.

[0014] In one example of the present disclosure, the machine tool further includes a third temperature sensor for detecting the temperature of the coolant stored in the first tank. The control unit obtains the temperature difference between the temperature detected by the second temperature sensor and the temperature detected by the third temperature sensor, and, if the pump is stopped, controls the cooling device so that the temperature obtained by adding the temperature difference to the temperature detected by the third temperature sensor approaches the temperature detected by the first temperature sensor.

[0015] In one example of this disclosure, the machine tool is further connected to the machining area. It includes a chip conveyor for collecting coolant discharged from the machining area and chips from the workpiece discharged from the machining area. The machining area includes an inclined surface located below the workpiece within the machining area. The machine tool further includes a discharge mechanism for discharging coolant toward the inclined surface. The flow path connects the pump and the discharge mechanism.

[0016] In another example of the present disclosure, a machine tool having a workpiece machining area includes a first tank for storing coolant, a cooling device for cooling the coolant stored in the first tank or the coolant before it is supplied to the first tank, a pump for drawing up the coolant stored in the first tank and supplying the coolant to the machining area, a second temperature sensor for detecting the temperature of the coolant stored in the first tank, a first temperature sensor for detecting the temperature of the components constituting the machine tool, and a control unit. The control unit controls the cooling device so that the temperature obtained by adding a predetermined value to the temperature detected by the second temperature sensor approaches the temperature detected by the first temperature sensor.

[0017] Another example of the present disclosure provides a method for controlling a machine tool having a workpiece machining area. The machine tool includes a first tank for storing coolant, a cooling device for cooling the coolant stored in the first tank or the coolant before it is supplied to the first tank, a pump for drawing up the coolant stored in the first tank and supplying the coolant to the machining area, a first temperature sensor for detecting the temperature of a component of the machine tool, and a second temperature sensor provided in a flow path connecting the pump and the machining area for detecting the temperature of the coolant flowing through the flow path. The control method includes the step of controlling the cooling device such that the temperature detected by the second temperature sensor approaches the temperature detected by the first temperature sensor.

[0018] Another example of the present disclosure provides a control program for a machine tool having a workpiece machining area. The machine tool includes a first tank for storing coolant, a cooling device for cooling the coolant stored in the first tank or the coolant before it is supplied to the first tank, a pump for drawing up the coolant stored in the first tank and supplying the coolant to the machining area, a first temperature sensor for detecting the temperature of the components constituting the machine tool, and a second temperature sensor provided in a flow path connecting the pump and the machining area for detecting the temperature of the coolant flowing through the flow path. The control program causes the machine tool to perform a process to control the cooling device so that the temperature detected by the second temperature sensor approaches the temperature detected by the first temperature sensor.

[0019] The above and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description relating to the invention, which will be understood in conjunction with the accompanying drawings. [Brief explanation of the drawing]

[0020] [Figure 1] This is a diagram showing the external appearance of a machine tool. [Figure 2] It is a diagram showing an example of a configuration for realizing a temperature control function. [Figure 3] It is a diagram showing the appearance of a chip conveyor. [Figure 4] It is a diagram showing a cross-section of a chip conveyor. [Figure 5] It is a diagram for explaining Specific Example 1 regarding the piping pattern of a flow path and the arrangement pattern of temperature sensors. [Figure 6] It is a diagram for explaining Specific Example 2 regarding the piping pattern of a flow path and the arrangement pattern of temperature sensors. [Figure 7] It is a diagram for explaining Specific Example 3 regarding the piping pattern of a flow path and the arrangement pattern of temperature sensors. [Figure 8] It is a diagram for explaining Specific Example 4 regarding the piping pattern of a flow path and the arrangement pattern of temperature sensors. [Figure 9] It is a diagram for explaining Specific Example 5 regarding the piping pattern of a flow path and the arrangement pattern of temperature sensors. [Figure 10] It is a diagram showing an example of the configuration of a drive mechanism in a machine tool. [Figure 11] It is a diagram showing an example of the hardware configuration of a control unit. [Figure 12] It is a flowchart showing the flow of control processing of a cooling device. [Figure 13] It is a diagram showing the device configuration of a machine tool according to the first modification example. [Figure 14] It is a flowchart showing the flow of control processing of a cooling device in the first modification example. [Figure 15] It is a flowchart related to the control processing of a cooling device in the first control mode. [Figure 16] It is a flowchart related to the control processing of a cooling device in the second control mode. [Figure 17] It is a diagram showing the device configuration of a machine tool according to the second modification example. [Figure 18] It is a diagram showing the device configuration of a machine tool according to the third modification example. [Figure 19]It is a diagram showing the device configuration of a machine tool according to a fourth modification example.

Embodiments for Carrying out the Invention

[0021] Hereinafter, each embodiment according to the present invention will be described while referring to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated. Note that each embodiment and each modification example described below may be selectively combined as appropriate.

[0022] <A. Appearance of Machine Tool 100> First, referring to FIG. 1, a machine tool 100 according to an embodiment will be described. FIG. 1 is a diagram showing the appearance of the machine tool 100.

[0023] As used in this specification, the “machine tool” is a concept encompassing various devices having a function of machining a workpiece. The machine tool 100 may be a horizontal machining center or a vertical machining center. Alternatively, the machine tool 100 may be a lathe, or other cutting machines, grinding machines, composite machining machines, 5-axis machining machines, etc. Further, the machine tool 100 is not limited to performing only removal machining, and may perform addition machining in addition to removal machining.

[0024] The machine tool 100 includes, for example, a cover body 130, a chip conveyor 150, and an operation panel 300. The cover body 130, also called a splash guard, forms the appearance of the machine tool 100 and partitions and forms a machining area AR for the workpiece.

[0025] The machine tool 100 processes a workpiece while discharging coolant into the machining area AR. The coolant used for machining causes the chips of the workpiece to flow from the machining area AR to the chip conveyor 150. The chip conveyor 150 separates the chips of the workpiece from the coolant and discharges the chips outside the machine tool 100 through the discharge port 27. The coolant from which the chips of the workpiece have been removed is reused for machining the workpiece.

[0026] The operation panel 300 is a general-purpose computer and has a display 306 for displaying various information related to machining. The display 306 is, for example, a liquid crystal display, an organic EL (Electro Luminescence) display, or other display device. Further, the display 306 is provided with a touch panel and accepts various operations on the machine tool 100 by touch operation.

[0027] <B. Coolant Temperature Control Function> The machine tool 100 includes a tank for storing coolant. The machine tool 100 pumps up the coolant from inside the tank using a pump and discharges the coolant into the machining area AR. At this time, it is preferable that the temperature of the discharged coolant does not fluctuate the temperature of the workpiece to be machined. Therefore, the machine tool 100 includes a cooling device for the coolant and controls the cooling device so that the temperature of the coolant approaches the reference temperature.

[0028] However, the coolant temperature rises due to the heat generated by the pump. As a result, the temperature of the coolant when it is discharged into the machining area AR may be higher than expected. In particular, the coolant used in machine tool 100 contains many foreign substances. These foreign substances include fine chips generated during machining. When pumping dirty coolant, the pump generates more heat than when pumping clean coolant. Therefore, the coolant used in machine tool 100 is particularly susceptible to the effects of heat generated by the pump. For example, the temperature of the coolant rises by about 1 to 2°C after passing through the pump. Therefore, machine tool 100 according to this embodiment controls the coolant cooling device taking into account the temperature rise due to the heat generated by the pump.

[0029] The following describes the coolant temperature control function of the machine tool 100 with reference to Figure 2. Figure 2 is a diagram showing an example of a configuration for realizing the temperature control function.

[0030] As shown in Figure 2, the machine tool 100 includes the aforementioned machining area AR, a tank 11 (first tank), a tank 12 (second tank), a control unit 50, a cooling device 55, a pump 60, a temperature sensor 70A (first temperature sensor), and a temperature sensor 70B (second temperature sensor).

[0031] Tanks 11 and 12 are each configured to store coolant. Tank 12 is equipped with a cooling device 55. Coolant cooled by the cooling device 55 is sent from tank 12 to tank 11 via the flow path R1.

[0032] More specifically, one end of the flow path R1 is connected to tank 11, and the other end of the flow path R1 is connected to tank 12. A pump (not shown) is installed inside tank 12. This pump pressurizes the coolant stored in tank 12 and sends it to flow path R1. As a result, the coolant cooled by the cooling device 55 is sent from tank 12 to tank 11 via flow path R1.

[0033] The cooling device 55 cools the coolant in the tank 12. The method of cooling the coolant is arbitrary. For example, the cooling device 55 cools the coolant by exchanging heat between the refrigerant and the coolant using a heat exchanger. The cooling device 55 can be, for example, a chiller. For example, the control unit 50 adjusts the cooling efficiency of the coolant in the tank 12 by controlling the flow rate of the refrigerant circulating within the cooling device 55. As another example, the control unit 50 adjusts the cooling efficiency of the coolant in the tank 12 by controlling the rotation speed of the fan that blows air to the heat exchanger in the cooling device 55.

[0034] Pump 60 is located inside tank 11 and is configured to pump up the coolant stored in tank 11. The coolant pumped up by pump 60 is sent to the machining area AR via flow path R2. One end of flow path R2 is connected to tank 11, and the other end is connected to the machining area AR. The control unit 50 controls pump 60 to pump the coolant CL stored in tank 11 into flow path R2. As a result, the coolant CL is discharged from flow path R2 to the machining area AR.

[0035] For the sake of explanation, in the following, the side of the coolant CL flowing through channel R2 that is closer to tank 11 will also be referred to as the "upstream side." On the other hand, the side of the coolant CL flowing through channel R2 that is closer to the machining area AR will also be referred to as the "downstream side."

[0036] The temperature sensor 70A is provided on any component of the machine tool 100 and is configured to detect the temperature of that component. Preferably, the temperature sensor 70A is provided on a component connected to the workpiece being machined. Examples of such components include the bed BD (see Figure 5) or the table TB (see Figure 5), which will be described later. By providing the temperature sensor 70A on a component connected to the workpiece, the temperature of the workpiece can be detected approximately. The temperature detected by the temperature sensor 70A is output to the control unit 50 as a reference temperature T0.

[0037] The temperature sensor 70B is installed in the flow path R2 connecting the pump 60 and the machining area AR, and is configured to detect the temperature of the coolant CL flowing through the flow path R2. In other words, the temperature sensor 70B is installed downstream of the pump 60 and upstream of the machining area AR. The temperature detected by the temperature sensor 70B is output to the control unit 50 as the coolant temperature T1.

[0038] The control unit 50 is a device for controlling the machine tool 100. An example of an object controlled by the control unit 50 is the cooling device 55. More specifically, the control unit 50 controls the cooling device 55 so that the coolant temperature T1 detected by the temperature sensor 70B approaches the reference temperature T0 detected by the temperature sensor 70A.

[0039] As described above, since the temperature sensor 70B is located downstream of the pump 60, it detects the coolant temperature after it has been affected by the heat generated by the pump 60. Therefore, the coolant temperature T1 detected by the temperature sensor 70B is the same as or approximately the same as the temperature at which it is discharged into the machining area AR. This allows the machine tool 100 to control the coolant temperature, taking into account the temperature rise due to the heat generated by the pump 60. As a result, coolant CL at the expected reference temperature T0 is discharged into the machining area AR.

[0040] In the example shown in Figure 2, the cooling device 55 is located in the tank 12, but the cooling device 55 may also be located in the tank 11. That is, the cooling device 55 only needs to be configured to cool the coolant stored in the tank 11 directly or indirectly. In other words, the cooling device 55 may be configured to cool the coolant stored in the tank 11, or it may be configured to cool the coolant in the tank 12 before it is sent to the tank 11. If the cooling device 55 is located in the tank 11, the tank 12 does not necessarily need to be located in the machine tool 100.

[0041] <Configuration of Chip Conveyor 150> Next, referring to FIGS. 3 and 4, the chip conveyor 150 shown in FIG. 1 described above will be explained. FIG. 3 is a view showing the appearance of the chip conveyor 150. FIG. 4 is a view showing a cross section of the chip conveyor 150.

[0042] The chip conveyor 150 is connected to the processing area AR and is configured to collect the coolant discharged from the processing area AR and the chips of the workpiece discharged from the processing area AR. As an example, the chip conveyor 150 is provided, for example, in the cover body 130 that partitions the above-described processing area AR.

[0043] The chip conveyor 150 has the above-described tank 11. The tank 11 is configured to store the coolant. The chip conveyor 150 conveys the chips of the workpiece contained in the coolant to a chip bucket (not shown) and discharges the clean coolant into the tank 11 by filtering the coolant.

[0044] The chip conveyor 150 further has a cover body 21. The cover body 21 forms the appearance of the chip conveyor 150. The cover body 21 has a housing shape that forms a space inside.

[0045] The cover body 21 has, as its constituent parts, a horizontal part 22, a chip receiving part 23, a rising part 26, and a discharge port 27.

[0046] The horizontal part 22 is placed in the tank 11. The horizontal part 22 has an appearance in the shape of a plate extending in the horizontal direction. The rising part 26 rises from one end in the longitudinal direction of the horizontal part 22 and extends obliquely upward.

[0047] The chip receiving section 23 is provided on the horizontal section 22. The chip receiving section 23 consists of a housing provided on the top surface of the horizontal section 22. The chip receiving section 23 is provided with a connection port 24. The connection port 24 consists of a through hole that penetrates the chip receiving section 23. The chip conveying device 13 is connected to the chip receiving section 23 through the connection port 24. The chip conveying device 13 consists of, for example, a trough extending in one direction and a spiral conveyor installed on the trough.

[0048] The discharge port 27 is located at the end of the rising section 26, which extends diagonally upward from the horizontal section 22. The discharge port 27 is an opening in the cover body 21 that opens vertically downward. Below the discharge port 27, a chip bucket (not shown) for collecting chips is installed. Chips from the workpiece discharged from the processing area are received into the cover body 21 by the chip receiving section 23. The chips are transported inside the cover body 21 by the chip transport section 35, which will be described next, and are discharged from the discharge port 27 and collected in the chip bucket.

[0049] The chip conveyor 150 further includes a chip transport section 35. The chip transport section 35 is housed in a cover body 21. The chip transport section 35 is a device for transporting chips within the cover body 21.

[0050] More specifically, the chip transport unit 35 includes a pair of endless chains 34, a drive sprocket 37, and a driven sprocket 38.

[0051] The drive sprocket 37 is located at the end of the rising section 26, which extends diagonally upward from the horizontal section 22. The drive sprocket 37 is positioned above the discharge port 27. The drive sprocket 37 is rotatably supported around an axis extending in a direction perpendicular to the plane of Figure 4 (hereinafter, this direction will also be referred to as the "width direction of the chip conveyor 150"). The output shaft of the motor MC (see Figure 10), which will be described later, is connected to the drive sprocket 37. The drive sprocket 37 rotates when power is transmitted from the motor MC.

[0052] The driven sprocket 38 is located in the bent section between the horizontal section 22 and the vertical section 26. The driven sprocket 38 is rotatably supported around an axis (axis AX1) that extends in the width direction of the chip conveyor 150.

[0053] A pair of endless chains 34 are arranged parallel to each other at a distance in the width direction of the chip conveyor 150. The endless chains 34 are wrapped around a drive sprocket 37 and a driven sprocket 38 and are guided by a plurality of guide members. When the drive sprocket 37 rotates, the endless chains 34 rotate in the direction indicated by arrow A (hatched arrow) in Figure 4.

[0054] The chip conveyor 150 further includes a filter mechanism 39. The filter mechanism 39 is located inside the tank 11 and removes foreign matter such as workpiece chips from the coolant that flows into the tank 11 from the processing area. As a result, the coolant received from the processing area is filtered, and clean coolant is discharged from inside the cover body 21 into the tank 11.

[0055] The filter mechanism 39 includes, for example, a drum filter 46. The drum filter 46 is housed in the cover body 21. The drum filter 46 is provided in the bent portion between the horizontal portion 22 and the vertical portion 26. The drum filter 46 is configured to remove foreign matter such as chips from the coolant flowing from the outside to the inside. The drum filter 46 has, for example, a cylindrical shape and forms an internal space 47 inside it.

[0056] The drum filter 46 is positioned such that its central axis extends in the width direction of the chip conveyor 150. The drum filter 46 is positioned such that its central axis coincides with axis AX1, which is the rotation center of the driven sprocket 38. The drum filter 46 is connected to the driven sprocket 38 at both ends in the axial direction of axis AX1.

[0057] In the above description, an example in which the filter mechanism 39 has the drum filter 46 has been described. However, the filter mechanism 39 is not limited to the drum filter 46. As an example, the filter mechanism 39 may be composed of a rectangular filter or a circular filter.

[0058] A coolant discharge portion 28 is formed in the cover body 21. The coolant discharge portion 28 is composed of a through hole penetrating the cover body 21. The coolant discharge portion 28 is provided so as to communicate the internal space 47 of the drum filter 46 with the external space outside the cover body 21. The coolant received into the cover body 21 through the chip receiving portion 23 enters the internal space 47 of the drum filter 46 and is filtered. The filtered coolant is discharged to the tank 11 through the coolant discharge portion 28.

[0059] <D. Arrangement Pattern of Temperature Sensor> As described above, the temperature sensor 70B for detecting the coolant temperature T1 is provided in the flow path R2 connecting the tank 11 and the processing area AR. The piping pattern of the flow path R2 is not particularly limited, and the temperature sensor 70B is arranged at an arbitrary position on the flow path R2.

[0060] Hereinafter, referring to FIGS. 5 to 9, specific examples 1 to 5 of the piping pattern of the flow path R2 and the arrangement pattern of the temperature sensor 70B will be described.

[0061] (D1. Specific Example 1) FIG. 5 is a diagram for explaining Specific Example 1 related to the piping pattern of the flow path R2 and the arrangement pattern of the temperature sensor 70B.

[0062] In this example, the temperature sensor 70B is located in a flow path that supplies coolant, which affects the temperature of the workpiece W. The coolant may be supplied directly to the workpiece or to a component connected to the workpiece (for example, a table TB or a jig JG). In other words, the temperature sensor 70B is located in a flow path that supplies coolant to the workpiece W or its vicinity in the machining area AR. This allows the temperature sensor 70B to detect the temperature of the coolant that affects the temperature of the workpiece W.

[0063] The machining area AR includes, for example, a bed BD, a table TB, and a spindle 132. Figure 5 shows a flow path R2A connecting the tank 11 and the spindle 132 as an example of a flow path R2.

[0064] The bed BD is the base portion that secures the main body of the machine tool 100. The bed BD is configured to support various components located inside the machine tool 100. For example, on the bed BD, Table TB A system is in place. Table TB A jig JG is fixed above. The workpiece W, which is the object to be worked on, is fixed to the jig JG.

[0065] The spindle 132 is located inside the housing 133 and is rotatably supported by the housing 133. A tool T for machining the workpiece W is mounted on the spindle 132. The spindle 132 machines the workpiece W by rotating the tool T around its axial direction and bringing the tool T into contact with the workpiece W.

[0066] A communication passage L1, which is a coolant discharge mechanism, is formed inside the main spindle 132. The communication passage L1 penetrates the inside of the main spindle 132 along its axial direction. One end of the communication passage L1 is connected to the flow path R2A.

[0067] Various types of tools can be mounted on the spindle 132. In the example shown in Figure 5, a tool T with a through passage L2 is mounted on the spindle 132. The through passage L2 extends from the connection surface between the tool T and the spindle 132 to the tip of the tool T, and penetrates the tool T along the axial direction of the spindle 132. Note that the opening of the through passage L2 formed in the tool T is not limited to being formed on the base end face or tip face of the tool T, but may also be an opening on the side of the tool T, for example.

[0068] The coolant pumped up by the aforementioned pump 60 flows in the order of flow path R2A, connecting passage L1, and through passage L2, and is discharged from the tip of the tool T to the workpiece W. This suppresses the heating that occurs when the tool T processes the workpiece W. In addition, the chips generated by processing the workpiece W are carried to the aforementioned chip conveyor 150.

[0069] In the example shown in Figure 5, a temperature sensor 70A for detecting the aforementioned reference temperature T0 (see Figure 2) is provided on the bed BD. In addition, a temperature sensor 70B for detecting the aforementioned coolant temperature T1 (see Figure 2) is provided on the flow path R2A. Thus, the temperature sensor 70B is provided on the flow path R2A downstream of the pump 60 and upstream of the main shaft 132.

[0070] In the above description, we explained an example in which the temperature sensor 70B is installed in the flow path R2A connected to the communication passage L1 (flow path) within the main shaft 132. However, the temperature sensor 70B may also be installed in the communication passage L1 (flow path) that passes through the main shaft 132.

[0071] (D2. Specific Example 2) Figure 6 is a diagram illustrating a specific example 2 relating to the piping pattern of the flow path R2 and the arrangement pattern of the temperature sensor 70B.

[0072] In the example shown in Figure 5 above, a spindle-through type spindle 132 was described in which coolant is discharged from the cutting edge of the tool T. However, the coolant discharge mechanism used in the spindle 132 is not limited to the spindle-through type. For example, the coolant discharge mechanism used in the spindle 132 may be a side-through type in which coolant is discharged from the end face of the spindle 132.

[0073] Figure 6 shows a flow path R2B as an example of a flow path R2, connecting the side-through main shaft 132 and the tank 11. The temperature sensor 70B mentioned above is installed in this flow path R2B. Thus, the temperature sensor 70B may be installed on the flow path R2B downstream of the pump 60 and upstream of the side-through main shaft 132.

[0074] As described above, the temperature sensor 70B may be provided in the flow path R2A (see Figure 5) for supplying spindle-through coolant, or in the flow path R2B (see Figure 6) for supplying side-through coolant.

[0075] (D3. Specific Example 3) Figure 7 is a diagram illustrating a specific example 3 relating to the piping pattern of the flow path R2 and the arrangement pattern of the temperature sensor 70B.

[0076] In this example, the coolant discharge mechanism 125C is provided on the ceiling of the machining area AR. The discharge mechanism 125C may also be provided on the side wall of the machining area AR. Furthermore, there may be one or more discharge mechanisms 125C provided in the machining area AR.

[0077] Figure 7 shows a flow path R2C as an example of a flow path R2, connecting the tank 11 and the discharge mechanism 125C. The temperature sensor 70B described above is installed in this flow path R2C. Thus, the temperature sensor 70B may be installed on the flow path R2C downstream of the pump 60 and upstream of the discharge mechanism 125C.

[0078] (D4. Specific Example 4) Figure 8 is a diagram illustrating a specific example 4 relating to the piping pattern of the flow path R2 and the arrangement pattern of the temperature sensor 70B.

[0079] As shown in Figure 8, the processing area AR has an inclined surface FL that is tilted with respect to the horizontal plane so that workpiece chips are directed onto the chip conveyor 150 described above. The inclined surface FL is located below the workpiece W in the processing area AR. The inclined surface FL is configured to become lower towards the inside.

[0080] In this example, the machine tool 100 is equipped with a discharge mechanism 125D for discharging coolant toward the inclined surface FL. The discharge mechanism 125D may be one or more. By discharging coolant toward the inclined surface FL, the discharge mechanism 125D discharges chips from the workpiece W from the machining area AR to the chip conveyor 150 described above.

[0081] Figure 8 shows a flow path R2D as an example of a flow path R2, connecting the tank 11 and the discharge mechanism 125D. The temperature sensor 70B described above is installed in this flow path R2D. Thus, the temperature sensor 70B may be installed on the flow path R2D downstream of the pump 60 and upstream of the discharge mechanism 125D.

[0082] (D5. Specific Example 5) The piping patterns for flow path R2 shown in the above-mentioned specific examples 1 to 4 may be combined as appropriate. Below, with reference to Figure 9, an example of a piping pattern combining the above-mentioned specific examples 1 to 4 will be described.

[0083] Figure 9 is a diagram illustrating a specific example 5 relating to the piping pattern of the flow path R2 and the arrangement pattern of the temperature sensor 70B.

[0084] In this example, channel R2A shown in Specific Example 1 is shown as a separate channel from channels R2B to R2D shown in Specific Examples 2 to 4. In the example in Figure 9, channel R2C is shown as the main channel, and channels R2B and R2D are shown as tributaries. However, the relationship between the main channel and tributaries in channels R2B to R2D is arbitrary.

[0085] More specifically, flow path R2C has branching points P1 and P2. Flow path R2B branches off from flow path R2C at branching point P1 and is connected to the main shaft 132. Flow path R2D branches off from flow path R2C at branching point P2 and is connected to the discharge mechanism 125D.

[0086] In this example, two pumps 60A and 60B are provided. More specifically, pump 60A is for flow path R2A, and pump 60B is for flow paths R2B to R2D, both located within the tank 11.

[0087] A first valve (not shown) is provided at the branching point P1. The type of the first valve is not particularly limited. For example, the first valve is a three-way valve that can adjust the flow rate of coolant sent from branching point P2 to the discharge mechanism 125D and the flow rate of coolant sent from branching point P2 to branching point P1. The opening degree of the first valve is adjusted, for example, by the control unit 50.

[0088] A second valve (not shown) is provided at the branching point P2. The type of this second valve is not particularly limited. For example, this second valve is a three-way valve that can adjust the flow rate of coolant sent from branching point P1 to the main shaft 132 and the flow rate of coolant sent from branching point P1 to the discharge mechanism 125C. The opening degree of this second valve is adjusted, for example, by the control unit 50.

[0089] In this example, the above-described temperature sensor 70B is provided in the flow path between the tank 11 and the branch point P2. During machining, the machine tool 100 constantly discharges coolant from the discharge mechanism 125D. Therefore, in the flow path between the pump 60A and the discharge mechanism 125D, the coolant constantly flows. By being provided between the tank 11 and the branch point P2, the temperature sensor 70B can constantly detect the coolant temperature.

[0090] In the above description, an example where the temperature sensor 70B is provided between the tank 11 and the branch point P2 has been described. However, the temperature sensor 70B may be provided between the branch point P2 and the discharge mechanism 125D.

[0091] <E. Driving Mechanism> Next, referring to FIG. 10, various driving mechanisms in the machine tool 100 will be described. FIG. 10 is a diagram showing a configuration example of the driving mechanism in the machine tool 100.

[0092] As shown in FIG. 10, as a configuration related to the driving mechanism, the machine tool 100 includes a control unit 50, motor drivers 111A to 111C, motors MA to MC, the above-described pumps 60A and 60B, and the above-described chip conveyor 150.

[0093] As described above, the pump 60A is a device for pumping the coolant into the flow path R2A (see FIG. 9). A motor MA is connected to the pump 60A. The motor MA may be an AC motor, a stepping motor, a servo motor, or other types of motors.

[0094] The motor MA is driven by the motor driver 111A. The motor driver 111A is composed of a control circuit, an inverter, and the like. The motor driver 111A receives an input of a control signal from the control unit 50 and outputs an alternating current having a frequency corresponding to the control signal to the motor MA. Thereby, the rotation speed of the motor MA changes, and the flow rate of the coolant pumped into the above-described flow path R2A is controlled.

[0095] As described above, the pump 60B is a device for pumping coolant through the flow paths R2B to R2D (see FIG. 9). A motor MB is connected to the pump 60B. The motor MB may be an AC motor, a stepping motor, a servo motor, or any other type of motor.

[0096] The motor MB is driven by a motor driver 111B. The motor driver 111B is composed of a control circuit, an inverter, etc. The motor driver 111B receives an input of a control signal from the control unit 50 and outputs an alternating current of a frequency corresponding to the control signal to the motor MB. Thereby, the rotational speed of the motor MB changes, and the flow rate of the coolant pumped through the above-described flow paths R2B to R2D is controlled.

[0097] A motor MC is connected to the above-described chip conveyor 150 (see FIG. 4). The motor MC may be an AC motor, a stepping motor, a servo motor, or any other type of motor.

[0098] The motor MC is driven by a motor driver 111C. The motor driver 111C is composed of a control circuit, an inverter, etc. The motor driver 111C receives an input of a control signal from the control unit 50 and outputs an alternating current of a frequency corresponding to the control signal to the motor MC. Thereby, the rotational speed of the motor MC changes, and the rotational speed of the conveyor in the chip conveyor 150 is controlled.

[0099] <F. Control Unit 50> Next, referring to FIG. 11, the above-described control unit 50 will be described. FIG. 11 is a diagram showing an example of the hardware configuration of the control unit 50.

[0100] The control unit 50 is a device for controlling the machine tool 100. The configuration of the control unit 50 is arbitrary. The control unit 50 may consist of a single control unit or multiple control units. As an example, the control unit 50 includes at least one of a PLC (Programmable Logic Controller) and a CNC (Computer Numerical Control).

[0101] The control unit 50 includes a control circuit 201, a ROM (Read Only Memory) 202, a RAM (Random Access Memory) 203, communication interfaces 204 and 205, and an auxiliary storage device 220. These components are connected to the internal bus 209.

[0102] The control circuit 201 is comprised of, for example, at least one integrated circuit. The integrated circuit may consist of, for example, at least one CPU, at least one GPU (Graphics Processing Unit), at least one ASIC (Application Specific Integrated Circuit), at least one FPGA (Field Programmable Gate Array), or a combination thereof.

[0103] The control circuit 201 controls the operation of the control unit 50 by executing various programs, such as the control program 222. The control program 222 defines instructions for controlling various devices within the machine tool 100. Based on receiving an execution instruction for the control program 222, the control circuit 201 reads the control program 222 from the auxiliary storage device 220 or ROM 202 into the RAM 203. The RAM 203 functions as working memory and temporarily stores various data necessary for the execution of the control program 222.

[0104] The communication interface 204 is an interface for enabling communication using LAN (Local Area Network) cables, WLAN (Wireless LAN), or Bluetooth (registered trademark).

[0105] The communication interface 205 is an interface for performing periodic communication with external devices using a field network. Examples of field networks include EtherCAT®, EtherNet / IP®, CC-Link®, or CompoNet®. The control unit 50 communicates with the aforementioned motor drivers 111A~111C, for example, via the communication interface 205.

[0106] The auxiliary storage device 220 is, for example, a storage medium such as a hard disk or flash memory. The auxiliary storage device 220 stores various information such as the control program 222 and setting parameters 224. The setting parameters 224 define various parameters that are referenced when the control program 222 is executed.

[0107] The storage location for the control program 222 and the setting parameters 224 is not limited to the auxiliary storage device 220, but may also be the storage area of ​​the control circuit 201 (e.g., cache memory), ROM 202, RAM 203, external devices (e.g., a server), etc.

[0108] Note that the control program 222 may be provided not as a single program but as part of an arbitrary program. In this case, various processes according to the present embodiment are realized in cooperation with an arbitrary program. Even a program that does not include such a part of the module does not deviate from the gist of the control program 222 according to the present embodiment. Further, some or all of the functions provided by the control program 222 may be realized by dedicated hardware. Further, the machine tool 100 may be configured in a form such as a so-called cloud service in which at least one server executes a part of the processing of the control program 222.

[0109] <G. Control Flow of Cooling Device 55> Next, referring to FIG. 12, the flow related to the control process of the cooling device 55 will be described. FIG. 12 is a flowchart showing the flow of the control process of the cooling device 55.

[0110] The process shown in FIG. 12 is performed by the control unit 50 executing the above-described control program 222. Note that some or all of the processes shown in FIG. 12 may be executed by circuit elements or other hardware.

[0111] In step S112, the control unit 50 acquires the reference temperature T0 from the above-described temperature sensor 70A.

[0112] In step S114, the control unit 50 acquires the coolant temperature T1 from the above-described temperature sensor 70B.

[0113] In step S120, the control unit 50 determines whether the coolant temperature T1 acquired in step S114 is higher than the reference temperature T0 acquired in step S112. When the control unit 50 determines that the coolant temperature T1 is higher than the reference temperature T0 (YES in step S120), the control is switched to step S130. Otherwise (NO in step S120), the control unit 50 switches the control to step S140.

[0114] In step S130, the control unit 50 controls the cooling device 55 described above so that the temperature of the coolant in the tanks 11 and 12 drops below the current temperature. As an example, the control unit 50 increases the flow rate of the refrigerant circulating in the cooling device 55 above the current rate. As another example, the control unit 50 increases the rotational speed of the fan provided in the heat exchanger in the cooling device 55 above the current speed. Thereafter, the control unit 50 returns the control to step S112.

[0115] In step S140, the control unit 50 controls the cooling device 55 described above so that the temperature of the coolant in the tanks 11 and 12 rises above the current temperature. As an example, the control unit 50 decreases the flow rate of the refrigerant circulating in the cooling device 55 below the current rate. As another example, the control unit 50 decreases the rotational speed of the fan provided in the heat exchanger in the cooling device 55 below the current speed. Thereafter, the control unit 50 returns the control to step S112.

[0116] Note that the acquisition process of the reference temperature T0 in step S112 does not necessarily need to be executed every time the acquisition process of the coolant temperature T1 in step S114 is executed. As another example, the acquisition process of the reference temperature T0 in step S112 may be executed only once at the start of the coolant temperature control process. Alternatively, the acquisition process of the reference temperature T0 in step S112 may be executed once every time the acquisition process of the coolant temperature T1 in step S114 is executed N times (N is a constant of 2 or more).

[0117] <H. First Modified Example>

[0118] (H1. Overview) Next, referring to FIG. 13, the machine tool 100 according to the first modified example will be described. FIG. 13 is a diagram showing the device configuration of the machine tool 100 according to the first modified example.

[0119] The machine tool 100 according to the first modification differs from the machine tool 100 described above in that it is further equipped with a temperature sensor 70C (third temperature sensor) in addition to temperature sensors 70A and 70B. Other points are as described above, so those explanations will not be repeated below.

[0120] The temperature sensor 70C is installed in the machine tool 100 to detect the temperature before it passes through the pump 60B. In the example shown in Figure 13, the temperature sensor 70C is installed in the tank 11.

[0121] In the modified machine tool 100, before the pump 60B stops, the temperature difference ΔT between the coolant temperature T1 detected by the temperature sensor 70B and the coolant temperature T1' detected by the temperature sensor 70C is obtained. The temperature difference ΔT corresponds to the rise in coolant temperature due to the heat generated by the pump 60B. Then, if the pump 52B is stopped, the machine tool 100 controls the cooling device 55 so that the temperature "T1'+ΔT", which is the coolant temperature T1' detected by the temperature sensor 70C plus the temperature difference ΔT, approaches the reference temperature T0 detected by the temperature sensor 70A.

[0122] Furthermore, bringing the coolant temperature "T1'+ΔT" closer to the reference temperature T0 is equivalent to bringing the coolant temperature T1' closer to the reference temperature "T0-ΔT".

[0123] (H2. Control flow of cooling device 55) Next, the control process of the cooling device 55 in this modified example will be explained with reference to Figures 14 to 16. Figure 14 is a flowchart showing the flow of the control process of the cooling device 55 in this modified example.

[0124] The process shown in Figure 14 is performed by the control unit 50 executing the control program 222 described above. Note that some or all of the process shown in Figure 14 may be performed by circuit elements or other hardware.

[0125] In step S110, the control unit 50 determines whether the pump 60B is operating. If the control unit 50 determines that the pump 60B is operating (YES in step S110), it switches the control to step S200A. Otherwise (NO in step S110), the control unit 50 switches the control to step S200B.

[0126] In step S200A, the control unit 50 executes the control process for the cooling device 55 in the first control mode. Figure 15 is a flowchart of the control process for the cooling device 55 in the first control mode.

[0127] The flowchart shown in Figure 15 differs from the flowchart shown in Figure 12 in that it includes step S116. Furthermore, the flowchart in Figure 15 differs from the flowchart in Figure 12 in that the process in step S110 is executed after the processes in steps S130 and S140. Other points are as described above, so their explanations will not be repeated.

[0128] In step S116, the control unit 50 stores the coolant temperature T1 obtained in step S114. For example, the coolant temperature T1 is stored in the auxiliary storage device 220 described above.

[0129] In step S200B, the control unit 50 executes the control process for the cooling device 55 in the second control mode. Figure 16 is a flowchart of the control process for the cooling device 55 in the second control mode.

[0130] In step S212, the control unit 50 obtains the reference temperature T0 from the temperature sensor 70A mentioned above.

[0131] In step S214, the control unit 50 obtains the coolant temperature T1' from the temperature sensor 70C mentioned above.

[0132] In step S216, the control unit 50 calculates the temperature difference ΔT between the coolant temperature T1 stored in step S116 and the coolant temperature T1' obtained in step S214. More specifically, the control unit 50 subtracts the coolant temperature T1' obtained in step S214 from the coolant temperature T1 stored in step S116 and calculates the result of this difference as the temperature difference ΔT.

[0133] In step S220, the control unit 50 determines whether the temperature "T1'+ΔT", obtained by adding the temperature difference ΔT to the coolant temperature T1' acquired in step S214, is higher than the reference temperature T0 acquired in step S212. If the control unit 50 determines that the coolant temperature "T1'+ΔT" is higher than the reference temperature T0 (YES in step S220), it switches the control to step S230. Otherwise (NO in step S220), the control unit 50 switches the control to step S240.

[0134] In step S230, the control unit 50 controls the cooling device 55 described above so that the temperature of the coolant in tanks 11 and 12 is lower than it is now. For example, the control unit 50 increases the flow rate of the refrigerant circulating in the cooling device 55. For another example, the control unit 50 increases the rotation speed of the fan provided in the heat exchanger of the cooling device 55. After that, the control unit 50 returns control to step S110.

[0135] In step S240, the control unit 50 controls the cooling device 55 described above so that the temperature of the coolant in tanks 11 and 12 rises above its current level. For example, the control unit 50 reduces the flow rate of the refrigerant circulating within the cooling device 55. As another example, the control unit 50 reduces the rotational speed of the fan provided in the heat exchanger within the cooling device 55. After that, the control unit 50 returns control to step S110.

[0136] Note that the acquisition process of the reference temperature T0 in step S212 does not necessarily need to be executed every time the acquisition process of the coolant temperature T1' in step S214 is executed. As another example, the acquisition process of the reference temperature T0 in step S212 may be executed only once at the start of the coolant temperature control process. Alternatively, the acquisition process of the reference temperature T0 in step S212 may be executed once every time the acquisition process of the coolant temperature T1' in step S214 is executed N times (N is a constant of 2 or more).

[0137] <I. Second Modified Example> Next, referring to FIG. 17, the machine tool 100 according to the second modified example will be described. FIG. 17 is a diagram showing the device configuration of the machine tool 100 according to the second modified example.

[0138] As shown in FIG. 17, the machine tool 100 according to this modified example is different from the above example in that it does not include the temperature sensor 70B and includes only the above-described temperature sensors 70A and 70C. Then, the machine tool 100 controls the above-described cooling device 55 so that the temperature "T1'+ΔT'", which is obtained by adding a predetermined value ΔT' to the coolant temperature T1' detected by the temperature sensor 70C, approaches the reference temperature T0 detected by the temperature sensor 70A.

[0139] The predetermined value ΔT' is defined, for example, in the above-described setting parameter 224 (see FIG. 11). The predetermined value ΔT' may be set in advance, may be arbitrarily set by the user, or may be automatically set.

[0140] As an example, the predetermined value ΔT' is greater than 0°C and less than 3°C. More specifically, the predetermined value ΔT' is a value of 1°C or more and 2°C or less. As another example, the machine tool 100 may predict the temperature rise caused by the pump 60B from past performance values and set the predicted value as the predetermined value ΔT'.

[0141] <J. Third Modified Example> Next, with reference to Figure 18, a machine tool 100 according to the third modified example will be described. Figure 18 is a diagram showing the device configuration of the machine tool 100 according to the third modified example.

[0142] In the example described above, the temperature sensor 70B is provided in the flow path R2 connecting the tank 11 and the processing area AR. However, the temperature sensor 70B may also be provided in the flow path connecting a different tank 14 to the processing area AR.

[0143] Tank 14 is a flat-mounted tank similar to Tank 11. In this modified example, contaminated coolant is stored in Tank 11, and clean coolant is stored in Tank 14. Tanks 11 and 14 may be configured as a single unit or as separate units.

[0144] More specifically, the machine tool 100 according to this modified example includes a tank 11, a tank 14, and a cyclone filter 400 as a sludge separation mechanism.

[0145] A pump 58A is provided in tank 11. Coolant drawn up by pump 58A is sent to cooling device 55 via flow path Ra. After being cooled by cooling device 55, the coolant is sent to tank 14.

[0146] Furthermore, a pump 58B is provided in the tank 11. The coolant drawn up by the pump 58B is sent to the cyclone filter 400 via the inlet pipe Rb0. The cyclone filter 400 is a mechanism for separating the coolant sent through the inlet pipe Rb0 into clean coolant and contaminated coolant by centrifugal force. The sludge content in the clean coolant is less than the sludge content in the contaminated coolant.

[0147] The cyclone filter 400 is connected to an inlet pipe Rb0, an outlet pipe Rb1, and an outlet pipe Rb2.

[0148] One end of the inlet pipe Rb0 is connected to the tank 11. The other end of the inlet pipe Rb0 is connected to the inlet of the cyclone filter 400.

[0149] The coolant sent to the cyclone filter 400 flows spirally inside the filter. During this process, heavy sludge falls with some of the coolant due to gravity and is discharged from the lower outlet of the cyclone filter 400. As a result, dirty coolant containing a large amount of sludge is discharged into the outlet pipe Rb2.

[0150] Furthermore, the cyclone filter 400 is equipped with a throttling mechanism 402. The throttling mechanism 402 is a mechanism for limiting the flow rate of contaminated coolant flowing through the outlet pipe Rb2. The throttling mechanism 402 acts as resistance, causing the coolant to rise in the opposite direction to gravity as it flows spirally inside the cyclone filter 400. As a result, clean coolant free of sludge is discharged into the outlet pipe Rb1.

[0151] One end of the outlet pipe Rb1 is connected to the upper outlet of the cyclone filter 400. The other end of the outlet pipe Rb1 is connected to the tank 14. Clean coolant is sent to the tank 14 via the outlet pipe Rb1.

[0152] Furthermore, a pump 60C is installed inside the tank 14. The pump 60C is configured to pump up the coolant stored in the tank 14. The coolant pumped up by the pump 60C is sent to the machining area AR via the flow path R2. One end of the flow path R2 is connected to the tank 14, and the other end of the flow path R2 is connected to the machining area AR. The control unit 50 controls the pump 60C to pressurize the clean coolant stored in the tank 14 into the flow path R2. As a result, the coolant is discharged from the flow path R2 to the machining area AR.

[0153] In the example shown in Figure 18, the flow path R2 is shown as the flow path R2A for discharging spindle-through coolant. The temperature sensor 70B is located in the flow path R2A that connects the tank 14 (first tank) and the machining area AR.

[0154] The machine tool 100 controls the cooling device 55 so that the coolant temperature T1 detected by the temperature sensor 70B approaches the reference temperature T0 detected by the temperature sensor 70A. As a result, the coolant temperature T1 discharged from the spindle 132 is the same as or approximately the same as the reference temperature T0.

[0155] As a result, the machine tool 100 can control the coolant temperature, taking into account the temperature rise of the coolant due to the heat generated by the pump 60C, and coolant at the expected reference temperature T0 is discharged into the machining area AR.

[0156] In the above description, we explained an example in which the temperature sensor 70B is installed in the flow path R2A connecting the tank 14 and the main shaft 132. However, the temperature sensor 70B may be installed in a different flow path.

[0157] As another example, the machine tool 100 has a tool post (not shown) for turning. The tool post is provided with a discharge mechanism configured to discharge coolant toward the workpiece. The temperature sensor 70B may be provided in the flow path connecting the tank 14 and the discharge mechanism of the tool post.

[0158] Furthermore, although the above description described an example in which the temperature sensor 70B is provided in the flow path R2A for discharging spindle-through coolant, the temperature sensor 70B may also be provided in the flow path for discharging side-through coolant.

[0159] Furthermore, the cooling device 55 may be provided in tank 11, in tank 14, or in another tank connected to tank 11 or tank 14.

[0160] <K. Fourth Modified Example> Next, referring to FIG. 19, a machine tool 100 according to a fourth modified example will be described. FIG. 19 is a diagram showing the device configuration of the machine tool 100 according to the fourth modified example.

[0161] In the above example, the case where the temperature sensor 70B is provided in the flow path R2 connecting the tank 11 and the machining area AR has been described. However, the temperature sensor 70B may be provided in a flow path connecting a separate tank 15 different from the tank 11 and the machining area AR.

[0162] The tank 15 is a vertical tank. The storage capacity of the coolant in the tank 11 is larger than the storage capacity of the coolant in the tank 15.

[0163] More specifically, the machine tool 100 according to this modified example includes the above-described tank 11, the above-described tank 12, and the tank 15.

[0164] A pump 59 is provided on the bottom surface of the tank 15. The pump 59 is configured to pump the coolant stored in the tank 15 to the tank 12 or the machining area AR via the flow path R1A. The coolant pumped to the machining area AR may be discharged, for example, from the ceiling of the machining area AR or may be discharged toward the above-described inclined surface FL.

[0165] Furthermore, a pump 60D is provided on the bottom surface of the tank 15. The pump 60D is configured to pump the coolant to the main shaft 132 via the flow path R2A. More specifically, one end of the flow path R2A is connected to the tank 15. On the other hand, the other end of the flow path R2A is connected to the tank 15.

[0166] Preferably, the above-described cyclone filter 400 is provided in the middle of the flow path R2A. As described above, an inflow pipe Rb0, an outflow pipe Rb1, and an outflow pipe Rb2 are connected to the cyclone filter 400.

[0167] The flow path R2A according to this modified example includes an inlet pipe Rb0 and an outlet pipe Rb1. More specifically, one end of the inlet pipe Rb0 is connected to the tank 15. On the other hand, the other end of the inlet pipe Rb0 is connected to the inlet of the cyclone filter 400.

[0168] In the example shown in Figure 19, the flow path R2 is shown as the flow path R2A for discharging spindle-through coolant. The temperature sensor 70B is located in the flow path R2A that connects the tank 15 (first tank) and the machining area AR.

[0169] The machine tool 100 controls the cooling device 55 so that the coolant temperature T1 detected by the temperature sensor 70B approaches the reference temperature T0 detected by the temperature sensor 70A. As a result, the coolant temperature T1 discharged from the spindle 132 is the same as or approximately the same as the reference temperature T0.

[0170] As a result, the machine tool 100 can control the coolant temperature, taking into account the temperature rise of the coolant due to the heat generated by the pump 60D, and coolant at the expected reference temperature T0 is discharged into the machining area AR.

[0171] In the above description, we explained an example in which the temperature sensor 70B is installed in the flow path R2A connecting the tank 15 and the main shaft 132. However, the temperature sensor 70B may be installed in a different flow path.

[0172] As another example, the machine tool 100 has a tool post (not shown) for turning. The tool post is provided with a discharge mechanism configured to discharge coolant toward the workpiece. The temperature sensor 70B may be provided in the flow path connecting the tank 15 and the discharge mechanism of the tool post.

[0173] Furthermore, although the above description described an example in which the temperature sensor 70B is provided in the flow path R2A for discharging spindle-through coolant, the temperature sensor 70B may also be provided in the flow path for discharging side-through coolant.

[0174] Furthermore, the cooling device 55 may be provided in tank 11, tank 12, tank 15, or another tank connected to tank 11, tank 12, or tank 15.

[0175] Other variations will be described. In the embodiments, a horizontal machining center was used as an example to illustrate the application of the present invention, but as mentioned above, it is not limited to this and can also be applied to turning centers, multi-tasking machines, etc. That is, the machine tool may have a work spindle that rotates a workpiece and a tool post that is provided so that a cutting tool, rotary tool, or other device can move between a cutting position and a retracted position by rotational movement. The tool post may be equipped with a turret that can rotate and index multiple tools, etc. Such a machine tool may be provided with a discharge port for supplying coolant to the workpiece from the vicinity of the tool post, and a second temperature sensor may be provided in the flow path connected to the discharge port. Alternatively, a coolant discharge port may be provided near the station on the turret to which the tool is attached. The second temperature sensor for measuring the temperature of the coolant may be provided in a flow path that passes through the turret, or in a flow path connected thereto. Alternatively, even if the flow path does not pass through the turret, the second temperature sensor may be provided in a flow path connected to a discharge section that discharges coolant from the vicinity of a tool, etc. provided at the station on the turret to the workpiece attached to the work spindle.

[0176] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0177] 11 Tank, 12 Tank, 13 Chip conveying device, 14 Tank, 15 Tank, 21 Cover body, 22 Horizontal section, 23 Chip receiving section, 24 Connection port, 26 Rising section, 27 Discharge port, 28 Coolant discharge section, 34 Endless chain, 35 Chip conveying section, 37 Drive sprocket, 38 Driven sprocket, 39 Filter mechanism, 46 Drum filter, 47 Internal space, 50 Control unit, 52B Pump, 55 Cooling device, 60 Pump, 60A Pump, 60B Pump, 60C Pump, 70A Temperature sensor, 70B Temperature sensor, 70C Temperature sensor, 100 Machine tool, 111A Motor driver, 111B Motor driver, 111C Motor driver, 125C Discharge mechanism, 125D Discharge mechanism, 130 Cover body, 132 Spindle, 133 Housing, 150 Chip conveyor, 201 Control circuit, 202 ROM, 203 RAM, 204 Communication interface, 205 Communication interface, 209 Internal bus, 220 Auxiliary storage device, 222 Control program, 224 Setting parameters, 300 Control panel, 306 Display, 400 Cyclone filter, 402 Dilating mechanism, A Arrow, AR Machining area, AX1 Axis, BD Bed, CL Coolant, FL Inclined surface, JG Fixture, L1 Connecting passage, L2 Through passage, MA Motor, MB Motor, MC Motor, P1 Branch point, P2 Branch point, R1 Flow path, R1A Flow path, R2 Flow path, R2A Flow path, R2B Flow path, R2C Flow path, R2D Flow path, Ra Flow path, Rb0 Inlet pipe, Rb1 Outlet pipe, Rb2 Outlet pipe, T Tool, T0 Reference temperature, T1 Coolant temperature, T1' Coolant temperature, TB Table, W Workpiece, ΔT Temperature difference, ΔT' Specific value.

Claims

1. A machine tool having a workpiece processing area, A first tank for storing coolant, A cooling device for cooling the coolant stored in the first tank, or the coolant before it is sent to the first tank, A pump for drawing up the coolant stored in the first tank and sending the coolant to the processing area, A first temperature sensor for detecting the temperature of a component constituting the machine tool, A second temperature sensor is provided in a flow path that connects the pump and the processing area, with one end opening into the processing area, for detecting the temperature of the coolant flowing through the flow path. It includes a control unit, The control unit controls the cooling device so that the temperature detected by the second temperature sensor approaches the temperature detected by the first temperature sensor, in a machine tool.

2. The machine tool according to claim 1, wherein the second temperature sensor is provided in a flow path that supplies coolant affecting the temperature of the workpiece.

3. The machine tool further includes a spindle configured to which a tool can be attached, The machine tool according to claim 2, wherein the second temperature sensor is provided in a flow path passing through the main spindle, or in a flow path connected to said flow path.

4. The machine tool according to claim 3, wherein the second temperature sensor is provided in a flow path for supplying spindle-through coolant or side-through coolant.

5. The machine tool further includes a tool post configured to accommodate a tool, The machine tool according to claim 2, wherein the second temperature sensor is provided in a flow path connected to a discharge port for supplying coolant from the tool post to the workpiece.

6. The machine tool according to any one of claims 1 to 5, wherein the member is a bed.

7. The aforementioned machine tool further, It is equipped with a second tank for storing coolant, The coolant stored in the second tank is sent to the first tank. The machine tool according to any one of claims 1 to 5, wherein the cooling device is provided in the second tank.

8. The aforementioned machine tool further, The system includes a third temperature sensor for detecting the temperature of the coolant stored in the first tank, The control unit, The temperature difference between the temperature detected by the second temperature sensor and the temperature detected by the third temperature sensor is obtained. The machine tool according to any one of claims 1 to 5, wherein, when the pump is stopped, the cooling device is controlled so that the temperature obtained by adding the temperature difference to the temperature detected by the third temperature sensor approaches the temperature detected by the first temperature sensor.

9. The machine tool is further connected to the machining area and includes a chip conveyor for collecting coolant discharged from the machining area and chips from the workpiece discharged from the machining area. The processing area includes an inclined surface located below the workpiece within the processing area. The machine tool further includes a discharge mechanism for discharging coolant toward the inclined surface, The machine tool according to any one of claims 1 to 5, wherein the flow path connects the pump and the discharge mechanism.

10. A machine tool having a workpiece processing area, A first tank for storing coolant, A cooling device for cooling the coolant stored in the first tank, or the coolant before it is sent to the first tank, A pump for drawing up the coolant stored in the first tank and sending the coolant to the processing area, A first temperature sensor for detecting the temperature of a component constituting the machine tool, A third temperature sensor for detecting the temperature of the coolant stored in the first tank, It includes a control unit, The control unit controls the cooling device such that the temperature obtained by adding a predetermined value to the temperature detected by the third temperature sensor, which corresponds to the temperature of the coolant sent from the pump to the machining area, approaches the temperature detected by the first temperature sensor.

11. A control method for a machine tool having a workpiece processing area, The aforementioned machine tool is A first tank for storing coolant, A cooling device for cooling the coolant stored in the first tank, or the coolant before it is sent to the first tank, A pump for drawing up the coolant stored in the first tank and sending the coolant to the processing area, A first temperature sensor for detecting the temperature of a component constituting the machine tool, A second temperature sensor is provided in a flow path that connects the pump and the processing area, with one end opening into the processing area, and is used to detect the temperature of the coolant flowing through the flow path. The control method comprises the step of controlling the cooling device such that the temperature detected by the second temperature sensor approaches the temperature detected by the first temperature sensor.

12. A control program for a machine tool having a workpiece machining area, The aforementioned machine tool is A first tank for storing coolant, A cooling device for cooling the coolant stored in the first tank, or the coolant before it is sent to the first tank, A pump for drawing up the coolant stored in the first tank and sending the coolant to the processing area, A first temperature sensor for detecting the temperature of a component constituting the machine tool, A second temperature sensor is provided in a flow path that connects the pump and the processing area, with one end opening into the processing area, and is used to detect the temperature of the coolant flowing through the flow path. The control program is a control program that causes the machine tool to execute a process to control the cooling device so that the temperature detected by the second temperature sensor approaches the temperature detected by the first temperature sensor.

Images